In the past, toners containing selenium and sulfide have been used on black-and-white prints to change the silver image hue to one that better conveys the mood or atmosphere of the subject. Proper disposal of these chemicals has always been required, even though environmental concerns were not as great as they are today. It is anticipated that further restriction will limit the use of these toners in the future. While still desirable, the traditional method of toning black-and-white prints will not be compatible with the new chromogenic black-and-white paper which uses color emulsions and couplers to create a neutral image with dyes rather than with silver as in traditional black-and-white photography. Because chromogenic black-and-white papers use dyes instead of silver, a dye bleach is necessary to change the hue.
Dye bleaching is used on EKTACHROME.TM. slides; however, color paper is not suitable for color adjustment by after treatment. Eastman Kodak publication E-70 states: "At this time there are no dye bleaches we can recommend for KODAK EKTACOLOR.TM. and EKTACHROME.TM. papers. The formulas previously published for use with earlier KODAK EKTACOLOR.TM. papers do not work satisfactorily with KODAK EKTACOLOR PLUS.TM. and Professional papers." The prior art has references to dye bleaching, such as Rubenstein U.S. Pat. No. 2,467,359 and Harder U.S. Pat. No. 4,990,430.